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Water will be used in a number of ways in the pit operation: <br />1) Control dust on the haul roads and excavation areas <br />Water used for dust suppression is usually 100 percent depletive with no measurable return <br />flows to the river system. Dust from the haul roads will be controlled by water. Water will <br />only be applied when needed at this elevation, since cold conditions on site for much of the <br />year result in little evaporation and /or dust. It is assumed that watering of roads will require <br />1700 gallons water 4x per day for 100 days per year. Other days will have natural moisture on <br />the roads or the site will be inactive since the annual production is not very high. This is <br />equivalent to 2.09 acre feet per year. <br />It is also assumed that minor amounts may be needed during very dry windy conditions during <br />the mining operation. This use is expected to be 1.2 acre feet per year. Therefore, the total <br />consumptive use for this category is 3.29 acre feet per year. <br />2) Crushing and Screening Plant Operations <br />The crushing/screening plant uses 200 gallons per hour at a throughput rate of 225 tons per hour, <br />but 180 tons per hour will be assumed, so this amount for 180 tons per hour is conservative. <br />Therefore, the total hours needed per year to produce the required tonnage is 522 hours. The <br />crusher will be an enclosed crusher with water sprays and the screen deck will also have sprays <br />at the entrance and on the screen deck itself. This is an amount of 0.32 acre feet per year. <br />Although the crusher /screen plant uses considerable water, it does not run for many hours during <br />the year to meet the annual production. <br />3) Wash plant operations <br />The wash plant will be used to remove fines from the material that will be used to make <br />concrete. Based on a throughput rate of 1000 tons per day, the plant will use 32,000 gallons of <br />water per day and will operate 24 days per year. This is a use of 2.36 acre feet per year. <br />Approximately 60% of this water will be recycled from the wash pond, but 40% will be <br />Uncompahgre Pit, February 2013 G -3 <br />